The present invention relates generally to tools and more particularly to tools designed principally for use in tapping applications.
Taps are cutting tools that are used to create a screw thread, or threading, in the surface that immediately defines a hole. In this capacity, a tap can be used to form a threaded female element (e.g., a nut) that is adapted to matingly receive a threaded male element (e.g., a bolt). As defined herein, use of the term “tapping” relates to both the act of creating screw threads in a previously unthreaded surface as well as the process of reshaping existing screw threads, which is also commonly referred to as “re-tapping” or “re-threading” in the art.
Taps that are designed to be manually operated are commonly referred to as hand taps. To create a threaded surface using a hand tap, a hole is first drilled or otherwise formed into a material, the diameter of the hole being slightly smaller than the diameter of the intended tap. With the hole formed, a hand tap is rotatably driven through the hole to cut the threading into the hole defining surface.
Although well known and widely used in the art, hand taps suffer from a number of notable shortcomings. Specifically, hand taps has been found to be, among other things, labor intensive, time consuming and relatively imprecise (i.e., prone to the introduction of human misalignment errors).
Accordingly, tapping attachments for motor driven machines are well known in the art. In particular, tapping attachments are commonly designed for use in connection with a conventional drill press. In this circumstance, the tapping attachment is coupled to the spindle for the drill press in coaxial alignment therewith (i.e., such that the tapping attachment is disposed in a generally vertical orientation). In use, the spindle is rotatably driven by the drill head motor, thereby similarly rotating the coaxial tapping attachment. With the material to be threaded positioned in place on the drill press table, a set of handles extending from a central hub are turned to vertically displace the spindle down towards the material to be threaded. Downward displacement of the spindle similarly coaxially aligns the tap attachment within the vertical bore in the material, the rotation of the tap attachment creating the tapping within the bore defining surface. Once the hole has been tapped to a desired distance, the direction of the rotation of the tap attachment is reversed in order to unthread the tap attachment from the workpiece.
Tapping attachments of the type described above often suffer from a notable shortcoming. Specifically, the vertical orientation of coaxially disposed tapping attachments renders its use relatively inconvenient and, on occasion, unfeasible when undertaken in work environments of limited size or when used to tap items that are long and/or irregular in shape.
Accordingly, tapping attachments that allow for radial tapping (i.e., tapping at an angle perpendicular to the longitudinal axis of a drill press spindle) are well known in the art. For example, in U.S. Pat. No. 5,358,362 to A. S. Johnson, there is disclosed a tapping attachment for use in connection with radial tapping comprises a tap spindle member rotatable in a tapping direction, a driven part engageable with a driving part from a power source in a different direction from the tapping direction, a forward drive member engageable with the tap spindle member to drive the tap spindle member in the tapping direction, a reverse drive member engageable with the tap spindle to drive it in a direction opposite to the tapping direction, means for transmitting drive to the forward drive member and the reverse drive member and engageable with the driven part for receiving drive and with the tap spindle member. The forward drive member and the reverse drive member are moveable axially along the tapping direction relative to the tap spindle member and upon relative axial movement in a direction opposite to the tapping direction, the forward drive member disengages from the tap spindle member and the reverse drive member engages in driving engagement with the tap spindle member to impart reverse rotation to the tap spindle member.
Although well known in the art, radial tapping attachments of the type described in detail above have been found to suffer from a couple notable drawbacks.
As a first drawback, radial tapping attachments of the type described above are typically mechanically complex in construction, thereby increasing overall manufacturing costs, which is highly undesirable.
As a second drawback, radial tapping attachments of the type described above provide limited tactile response to the operator, thereby increasing the likelihood of tapping imprecision, which is highly undesirable.